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std/collections/min_by.ts

Deno standard library
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// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
/** * Returns the first element that is the smallest value of the given function or undefined if there are no elements. * * Example: * * ```ts * import { minBy } from "https://deno.land/std@$STD_VERSION/collections/mod.ts"; * import { assertEquals } from "https://deno.land/std@$STD_VERSION/testing/asserts.ts" * * const people = [ * { name: 'Anna', age: 34 }, * { name: 'Kim', age: 42 }, * { name: 'John', age: 23 }, * ]; * * const personWithMinAge = minBy(people, i => i.age); * * assertEquals(personWithMinAge, { name: 'John', age: 23 }); * ``` */export function minBy<T>( array: readonly T[], selector: (el: T) => number,): T | undefined;export function minBy<T>( array: readonly T[], selector: (el: T) => string,): T | undefined;export function minBy<T>( array: readonly T[], selector: (el: T) => bigint,): T | undefined;export function minBy<T>( array: readonly T[], selector: (el: T) => Date,): T | undefined;export function minBy<T>( array: readonly T[], selector: | ((el: T) => number) | ((el: T) => string) | ((el: T) => bigint) | ((el: T) => Date),): T | undefined { let min: T | undefined = undefined; let minValue: ReturnType<typeof selector> | undefined = undefined;
for (const current of array) { const currentValue = selector(current);
if (minValue === undefined || currentValue < minValue) { min = current; minValue = currentValue; } }
return min;}